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Abstract.  The secondary production and population dynamics of the mole crab Emerita brasiliensis Schmitt, 1935 (Decapoda: Hippidae) were studied by taking monthly samples from June 1993 to May 1995 at each of three intertidal transects at Prainha beach, Brazil. The lifespan was ca. 8 months for males and females, but females showed higher growth, mortality, secondary production, and turnover rate. The higher production in spring versus autumn and winter was related to intense recruitment during that period. The population production was estimated at between 39.86 and 46.88 g (AFDW) · m−2 · a−1 for the first year (June 93–May 94) and between 150.95 and 156.07 g (AFDW) · m−2 · a−1 for the second year (June 94–May 95); the mean annual biomass was 4.91 and 23.09 g (AFDW) · m−2, respectively. High P/B rates, between ca. 6 and 9 · a−1, reflected the fast growth, high mortality, and low lifespan of the population, characterized by a high percentage of recently recruited individuals.

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The natural diet of Hepatus pudibundus in Fortaleza Bay, Ubatuba (SP), Brazil, was determined, based on two methods: Frequency Occurrence and Percentage Points. Foregut contents of 219 specimens collected from November 1988 to October 1989 in 7 different areas of Fortaleza Bay were analyzed. Hepatus pudibundus had varied recognizable food categories, in decreasing order: crustaceans, fish, sediment (a facultative scavenger), and molluscs. Other food categories were in low percentage: bryozoans, algae, annelids, foraminiferans, cnidarians, and echinoderms ranked fifth through tenth on the basis of the methods utilized. A significant difference was found in the amount of food in the diet during seasonal analysis (autumn 홢 summer 홢 winter 홢 spring) and among the 7 sampling areas of Fortaleza Bay. We suggest that the crab H. pudibundus is an opportunistic omnivorous crustacean, and is not exclusively molluscivorous.Different methods have been used to quantify food items, such as Frequency of Occur-

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The population structure, growth and production of the trigonal clam Tivela mactroides were investigated by monthly sampling between January 2003 and October 2004 in two areas (southern and northern) of the intertidal and subtidal zones of Caraguatatuba Bay, Southeastern Brazil. Intertidal sampling was carried out in each area along eight transects perpendicular to the shoreline. In the subtidal zone of both areas, one 50-m dredging was performed along five sampling stations arranged on three transects perpendicular to the coast. The intertidal abundance of T. mactroides was higher in the southern (more dissipative conditions) than in the northern area. High abundances occurred in February-March 2004 in the south and in September 2004 in the north. The size structure showed that younger individuals dominated in the sublittoral, indicating that recruitment occurs in this zone, followed by the migration of these individuals to the intertidal, where they complete their life cycle. Tivela mactroides showed continuous reproduction, with 26 cohorts detected in the study period. The lower estimates for the growth index (/′ = 3.22), mortality rate (Z = 2.10 year À1 ) and turnover rate (P/B = 1.21 year À1 ), and conversely the longer life span (2.5 years) of T. mactroides in Caraguatatuba Bay (24°S) compared with Venezuelan populations (10°N) suggests a latitudinal pattern of these life-history traits. The high production of T. mactroides in Caraguatatuba Bay was due to continuous recruitment and rapid and continuous growth, and demonstrates the importance of T. mactroides as a biological resource for many marine species and for the local residents.

The somatic and gonad productions of the cirolanid isopod Excirolana armata were analyzed by taking monthly samples from December 2003 to November 2005 on Una beach, São Paulo state (24°S), southeastern Brazil. Sampling was performed along three fixed transects established from the base of the foredunes to the waterline. Weight-specific growth rate was used to estimate the E. armata somatic production for 2004 and 2005, separately. The gonad production was estimated based on the monthly reproductive potential (mean number of eggs/ embryos per female 9 monthly abundance of ovigerous females with near-release broods) for 2004. The annual somatic production of E. armata population varied from 15.57 to 17.25 g AFDW m -1 year -1 and the somatic production/biomass ratio (P s /B) from 3.55 to 3.14 year ) contributed about 15 and 6% to the total production (P s ? P g ) of females and the population, respectively. The proportion of gonad to somatic production of females (P g /P s ) increased with individual size (ca 90% in the 7.5 mm size class), and the annual weight-specific gonad production (P g /B ratio) was estimated to 0.24 year -1 . The high P s /B ratios estimated for E. armata derive from the fast growth of individuals and show the importance of this population to the energy flow on Una beach ecosystem. However, the low percentage of juveniles verified in this population and in other studies of populations of the genus Excirolana is discussed as an important source of underestimation of P s /B ratio.

Using data available from the literature, patterns of biomass, production and productivity of sandy-beach macrofauna populations were examined, considering environmental (temperature, exposure, grain size and beach slope) and biological variables (life span and mean body mass) and feeding and taxonomic groups. A total of 102 estimates of both production and biomass and 105 estimates of P/B ratios were collected from 52 studies carried out between 42°46′S and 54°05′N, for 83 sandy-beach macrofauna populations. The negative relationship between P/B ratio and beach slope for the supralittoral amphipods agrees with the Habitat Safety Hypothesis, according to which these forms would show higher mortality in dissipative than in reflective beaches. The observed higher production of filter-feeders in exposed than in sheltered beaches suggests that more food is available for filter-feeders in exposed beaches. The higher production of filter-feeders (represented by bivalves and decapods), than of scavengers/predators (peracarids and gastropods) showed the importance of filter-feeders in the food web of sandy beaches. The P/B ratios were strongly related to life span, but weakly or not related to the mean body mass. The high amphipod P/B ratio was attributed to the short life span of these crustaceans; conversely, gastropods showed the lowest P/B ratio, in accordance with their longer life span. The observed differences in biomass, production and P/B ratios within crustaceans and molluscs were attributed to differences in life-history traits and feeding mode.